Create, read, update and delete (CRUD) are functions typically associated with persistent storage, such as the storage provided to a database, a file server, an application, or a web service. For example, structured query language (SQL) supports CRUD by using the following SQL commands: an INSERT to provide the create, a SELECT to provide the read, an UPDATE to provide the update, and a DELETE to provide the delete. Although CRUD is useful, CRUD provides limited functionality, especially in connection with more complex systems.